In a letter sent to Sir Terry Leahy, head of Tesco, several authors have come out against the supermarket leader's recent filing of defamation actions against its critics in Thailand. They include Lisa Appignanesi, the current President of the English section of PEN (Poets, Essayists, and Novelists), the international association of writers. Tesco is also pursuing a defamation action against the Guardian newspaper. Read more here.